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Has anyone achieved autonomous takeoff and landing with ArduPilot?

Posted by Michael on April 12, 2009 at 7:16pm
Has anyone achieved autonomous takeoff and landing with ArduPilot yet? If so can you share with everyone how you accomplished it. I have been wondering how to achieve this and what additional sensors / hardware will be required. Is it just a matter of setting way points and triggering certain tasks to take place at those way points for both take off and landing, or is there another way to accomplish this?
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Flight tests with ArduPilot in EasyGlider Pro

Posted by Bryan Cuervo on April 12, 2009 at 8:46am
I posted an earlier blog with pictures on how I placed the avionics in an EasyGlider Pro for autonomous flight. I found out that was the easy part! Now I’m performing flight tests to hone in on the code mods for stable flight ( as Jordi states, the latest code is optimized for the EasyStar). My method has been:Fly and observe performance in autonomous mode – record observations – make code modifications on laptop – remove GPS and upload code – replace GPS – fly again. Laborious but also fun since physical computing yields immediate effects that you get to see.I’ve attached a table I made in Excel to organize my iterations and keep me on track. Maybe this will help others in the same situation. One mistake I made was getting in a hurry to go fly. I could have found out about the reversed servo throws and IR sensor placement by just walking the plane around on the ground and changing its attitude by hand. This would have avoided the “death spirals” I experienced on that first day of flying!Bryan

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Groundstation

Posted by Boomslang on April 12, 2009 at 6:00am

OdysseyThis is a unit for a full size plane, but it would be nice if the GCS could look something like that when it's done!! This unit also have a very impressive list of features. Wonder if one can use it as a GCS+AP and have only the sensors with Xbee on the plane.
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heat seeking blimp

Posted by Aaron Weinstein on April 11, 2009 at 6:00pm
Hey everyone,I haven't been on the site in a while and I am amazed at what is/has come out of this community in the past 8 months.Anyway, I made a blimp last year for a class at RISD taught by Paul Badger. The blimp follows people. Its based around the arduino, a pyroelectric sensor, and an ultrasound sensor. The code is quite simple: it scans for heat (IR at ~ human frequency) and once it finds a maximum above threshold, it moves towards the location of heat and corrects for height.I started out with some mathematically complex programming but soon learned that very simple rules performed satisfactory. I don't plan on adding any more advanced controls or processes: its simple, stupid, and fun.A video of the blimp is here.also on the video is some other stuff I've done including a drawbot that draws in polar coordinates, and a bicycle powered record player (hah, not done).
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Radio for sale:

Posted by Robert Drone on April 11, 2009 at 7:18am
What does anyone think of this radio:http://www.nitroplanes.com/72waraco4chf.htmlWalkera Radio Control 4 Channel FM Transmitter Perfect for Helicopter and Airplane4 Channel R/C Set included, complete Left/ Right, Up/ Down Control ( RUDDER, AILERON, ELEVATOR AND THROTTLE. Suitable for Indoor / Outdoor / Backyard / Park ( 500 sqft area )Includes:One 4 Channel FM Transmitter w. Tx Battery holderOne ReceiverOne Crystal SetOne Receiver Battery Box w/ BEC connectorTwo 9 Gram ServosOne Switch HarnessOne Tx AntennaBattery HolderRequires: 8 AA batteriesRegular price: $99.95Sale price: $44.95It looks good to me and very affordable. What does every one else think?Link:http://www.nitroplanes.com/72waraco4chf.html
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The first steps.

Posted by Jonas on April 11, 2009 at 6:57am
Well today I am verry close finishing my first plane with a autopilot.So it is time for some contribution to this fantastic site.First I like to thank Chris Anderson and Jordi for all the effort they made!!I really like what you have done so far!!!
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glad to find the net page

Posted by yuanzhenzong on April 11, 2009 at 12:59am
as an engineer worked for uav,I need variety of knowledge about the system.It includes composite material Aerodynamics,propultion,avinics,payload(op or ir sensor)and the communication.because the real enrienment of education in my country,I haven't get the valuable material about that,today find this page and find kinds of products and subsystems,thank you.
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Starting a new ground station

Posted by Kyle Corbitt on April 10, 2009 at 7:30pm
Hey everyone, I would like to take this opportunity to post a screenshot of the groundstation I've just begun work on. I haven't gotten very far in the short time I've been working on it, but my goal is to release it around the same time as the upcoming ArduPilot Pro, which should have the ability to use a two-way digital radio for control. That gives me a good chunk of time for development and tuning.

I've put more time into playing around with different layouts than anything else so far, and I think I've settled on one that seems servicable. I would greatly appreciate it though if other community members (particularly those involved with ArduPilot Pro development) could let me know what you think of the direction I'm going... it would be much better to know sooner than later if I'm barking up the wrong tree!I should also mention that currently the "File" menu is set up as follows:"Load MissionSave Mission-------------Import KMLExport KML-------------Load PlaybackSave Playback-------------Exit"(there is nothing under "Settings" yet)Finally, for anyone interested in the code itself, I've been developing in Python using wxPython for the GUI elements.
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Ardupilot RF Interference?

Posted by Roy Stevens on April 10, 2009 at 3:21pm
I've been having some problems intermittently with RF interference when flying my Nexstar EP. I always thought it was just some local interference which kicked on and off for whatever reason and that I needed to just do a range test before each flight.However, just today I decided to try a range test with & without Ardupilot installed. With Ardupilot I could only go about 200 feet away before i started getting pretty significant twitching of the servos. Without Ardupilot everything was still rock solid at 200+ feet. So it looks like the jumble of wires I had inside before won't work... are there any special precautions I can take besides just organizing wires and keeping Ardupilot as far from the receiver as possible? Is it important to keep Ardupilot away from the ESC as well? Does anyone have any home-made RF shield ideas?I also want to thank Chris & Jordi for making Ardupilot - not only a great autopilot but a really great place for beginners to start learning.
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A bored teen's project:

Posted by Robert Drone on April 10, 2009 at 8:00am
Hi, I'm a bored teen living in south Georgia; so how's that different from any other teen? Well, I'm bored because what they teach us n school here is stuff I've known for a long time for the most part sooo I was looking around at airplanes online thinking about building a UAV and I came across this site after a while I got permission from my parents to use this site and here I am. I just posted some pictures of my custom airframe I am building and some electronics gear I could hack. I am a noob to real rc models (you know brushless motors and servos and stuff) the only real experience I have is the lego robotics system and messing with junked electonics and stuff. I was wondering if any one could answer the following questions:1. Has anyone launched an NXT or RCX using an all electric aircraft?2.Should I use the monster-truck rc unit to save money or buy a new one?(it is old so it is not proportional)3.Do you have to use a brushless and brand new battery?(could I use the one pictured)4.Could I build a magnetic sensor for the rcx or nxt?5. Does anyone have any comments questions or ideas for me?Here is a link to my pictures:

for some reason it stopped working so here is the page:http://www.diydrones.com/photo/photo/listForContributor?screenName=2le2rve18t2rmThanks,-Robert Drone:)
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LocoSys LS20031 GPS upgrade to 10Hz

Posted by Reto on April 10, 2009 at 2:18am
08975-03-L_i_ma.jpgI had some regular e-mail contact with LocoSys since I bought my 5Hz LS20031 GPS board from Sparkfun.LocoSys informed me that in June or July, they are going to propose an upgrade applicable to the LS20031. The GPS will then be able to have a 10Hz update rate.I'll post more information when available. in the meantime, here's the latest LocoSys product table for those interested: 2009DM.pdf
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Xbee socket board

Posted by Reto on April 10, 2009 at 1:00am
XBeeBreakout-01-L_i_ma.jpgWhile testing my setup, it often disturbed me that the Xbee Pro doesn't have a led somewhere to show it's powered up.Since I mount it onto a ply through an Xbee breakout board like the one on the picture, I just soldered a small red led between the VCC and GND. Now I know when it's powered ok without having to setup all Xbee transmission line.Of course, the led doesn't tell me if the Xbee is transmitting/receiving.
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To relax from programing, assembling, building, soldering, and tweaking (and maybe repairing): nice aerial videos

Posted by Reto on April 9, 2009 at 2:25pm
Not to make publicity here, but a young guy I came to correspond with is running an FPV stuff online shop (RC-Tech in Switzerland). He practices himself, of course, is very much involved in the FPV community, and, over that, has some real good sense for bringing up nice aerial video footage mostly based on the RF video material he's selling.On the web site, he's got some very enjoyable footage (in my opinion). It's a nice place to relax a bit from our UAVs developments. I am sure you'll enjoy most of them. There are some real plane videos too which are good, especially the Extra 300 flight with many different airborne camera views. The FPV comes mostly from page 2 on.Foamy slow flyers, watch that one: "Low And Slow"... crazy tree slalomingEasyGlider fans, look here.Esky Belt-CP carbon edition heli and screaming guitar solos, watch this one.There's even food for the X-Twinners... micro FPV!I'm sure there will be at least one interested in this alpine scenery of Crans-Montana or this other in Les Diablerets with the Altus XL.Finally some town night flying (but who wants to hide between parked cars at night with a black hood on his head to cover an alien video google?!?). Well, I was young some time ago, too...I wish all a enjoyable watching, a nice Easter (for those concerned), and everybody a fine week-end.
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Things are moving forward!

Posted by Tom Yochum on April 9, 2009 at 9:08am
Brian and I are moving forward at a good pace. As he wrote in his blog, we have our processor board in hand and the IMU is on its way. Yeah!I have been busy with a few tasks:1. Aircraft selection.I am pretty set on buying the AXN Floater Jet. It is inexpensive, durable (foam construction with pusher prop), and comes with aileron control. I will probably put in the order this weekend unless there are objections from Brian.2. AHRS developmentWe would like to use our IMU as the basis for an AHRS (attitude-heading reference system). An AHRS is basically an inertial navigator without the position information. To get this to work I first need an alignment algorithm. The IMU would need to be stationary while the accelerometers and gyros make measurements. The accelerometers sense the gravity vector, and this information is used to determine the pitch and roll. The gyros measure the earth's rotation and, with the help of the pitch and roll information, determine the heading relative to true north. I understand the theory, but I haven't worked out the math yet. It should be a fun problem!Once the AHRS is aligned, the accelerometer and gyro data is continuously integrated using the strapdown equations to provide the orientation of the aircraft. I have much of the AHRS code written already from a previous project. If it works remains to be seen! :-)3. Simulation developmentI did some searching and found a wonderful resource: Aerosim blockset for Simulink. It is free for educational and non-profit users. It has all the 6-DOF equations, aerodynamic equations, environmental equations, etc, for modeling an aircraft. Yeah!Now I need to get all the information about the aircraft we purchase into this model. Well, once we order an aircraft. There are a few parameters that I'm not sure how to estimate. Does anyone have a good way of estimating the moments of inertia of an RC aircraft? Also, I could use some help modeling the engine (power consumption, torque, rotation speed, etc).Once we have a simulation we can begin control law development. I am hoping to use modern control with full-state feedback. We'll see how that goes once we get there.Another feature that Brian and I would like to implement is hardware-in-the-loop simulations using Simulink. However, I don't have the Simulink add-ons for the communication. Does anyone know of some free/inexpensive software that does this?I should get back to my "real" job. As always, advice and feedback is greatly appreciated!Tom
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Platform progress

Posted by Brian Hudson on April 8, 2009 at 11:51pm
Tom and I have made a couple of decisions and are moving forward."I would not be just a nothin' my head all full of stuffin'...If I only had a brain."I purchased and have received a standard Arduino Duemilanove board. I strongly considered the ArduPilot, but I wanted to get up an running quickly and I didn't really want to spend the money for an FTDI Serial / USB cable. I've been doing some basic bootstrapping to get a few things up and running.- A simple echo terminal program as my first "hello world" type sketch- A "random" number generator set up to send data to a terminal program on the PC- A C# program to plot the data received from the number generator. Which brings me to my first request for advice / feedback in this post:Does anyone have recommendations for a set of plotting / graphing tools? Tom has a student copy of MatLab / Simulink, so I was thinking about seeing what could be done there, but I want something we can both use without me having to try to find time on his computer. I've considered Processing, but I don't really see a way to interface it easily with other software packages, and while I can't sum up succinctly why, it just doesn't seem like a language I want to invest much in. For now I've just used a free-ware copy of something called PlotLab - http://www.mitov.com/html/plotlab.html. The docs aren't very good, and it doesn't seem all that well suited to my current task, but it lets me get something on the screen quickly in a nice friendly C# .Net rapid development setup. It has some cool zoom features as well.The last thing I've written is a little quick and dirty benchmark sketch for floating point operations. I was just trying to get a ballpark here, but I can't recall where I placed the data. Either way, this wasn't very scientific. If folks have data about the efficiency of the floating point emulation sitting around somewhere, I've done some searching and haven't found much. Otherwise, this could be the topic of its own short post, although I'm by no means an expert in this area.Moving along...Input! More Input!Just today I placed the order for an Atomic IMU 6DOF sensor assembly. This was a relatively big purchase for us, but the combination of sensors set up according to manufacturer recommendation, a great little form factor package, and a programmable AVR core seemed to really fit our needs.Under ConstructionThis brings me to my next planned task - I will be writing a simple software-serial pass-thru sketch so that I can hook up the Atomic IMU 6DOF to a terminal program on the PC, play with it, and chart the output at least as a simple benchmarking / verification setup (remember I was too cheap to buy the FTDI serial / usb cable).Following that, I think my next (larger) task will be designing a serial communication protocol between the main Arduino board and the Arduino on the 6DOF. I don't want to reinvent the wheel here, so once I spec what my requirements are, I'll be hunting around for something I can base my protocol on. Here are some characteristics that come to mind, but I'm definitely not saying these are exhaustive or all necessary - obviously some are mutually exclusive, and I have some decisions to make between them:1) High speed - I want to be able to pull data at as high a frequency as our processing / navigation model needs.2) Low latency - pull model - the main controller requests data, and it gets it fast. If we're sampling very frequently, I don't want latency to indroduce complexity or inconsistency into our control / feedback model. I haven't yet quantified this at all.3) Low encoding overhead cost (the pull model kind of pushes against this goal, as there's more back and forth than perhaps necessary)4) Simple and consistent frequency samples - push model - the IMU pushes data at a consistent interval. I like the simplicity of this, but I don't want to burden the main controller with servicing and throwing away serial data that it's not going to use, wasting precious cycles.5) Flexible and extensible - Right now, I'll be using this to pull raw data straight from the sensors, either with a push or a pull model. If I go with the pull model, in order to achieve low latency I'll want some sort of request batching and transmission mechanism, which I would want to lend itself well to future expansion of the data supported. This may all be overkill, and I might just end up defining a set of metrics on both sides that grows as my needs grow.Once I've got an idea of my data transfer system, another need I'll have is the ability to program the AVR on the 6DOF. I've got a couple important issues here, in priority order:1) Fail-safe, Fail-safe, Fail-safe. I'm a bit nervous about programming an SMD chip on a $125 part. I've never programmed an Atmel before (ok fine, I've programmed my Arduino several times now, but that hardly counts). My previous experience was with the PIC microcontrollers that took minutes to program and 20 minutes in a UV light box to "erase," so my guess is that ICSP is going to be a welcome change - I sure hope so, as I have no desire to screw this baby up and get my first shot at SMD soldering with my nearly non-existent soldering tools, and very limited soldering skills. Words of encouragement and "you can't break it by flashing it, I swear!" are definitely appreciated here.2) I'm cheap :) I'm not about to drop $20+ for an AVR programmer when I've got a 16Mhz amazingly programmable physical computing platform right in front of me! I've seen far more Arduino AVR programmer set ups than I expected to when I came up with this idea and did a search, so I'd love feedback about experience folks have here if any. What sketch program did you use? What software did you use with it? My Duemilanove has the ATMega328, so I'll need something current, I think.I'm hoping Tom will be writing a post similar to this about our progress on our choice of plane. Our ever current theme of getting the most for our money has led to a fairly involved spreadsheet with our candidate airframes, their characteristics, and the cost of all the equipment to get them up and running:

Thanks to Chris for the tip on fixing up this image so you can click it for a larger version. I have links to all the parts in the cells of the spreadsheet, but obviously they're too long to make fully visible, so folks looking at the image don't know what the dollar amounts translate into in terms of parts, but like I said - hopefully Tom will post on this later!
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